‪Create Excel files with multiple sheets in C#, VB.NET, Java, C++, PHP and other! EasyXLS™ library allows you to create Excel files with multiple sheets. There are two types of sheets: worksheets and chart sheets.
http://www.easyxls.com/manual/basics/create-excel-file-multiple-sheets.html

One of the challenges when creating Excel files is to protect the data inside the sheets from unintended editing or to restrict the access to data from some cells.

An Excel file has a feature that allows to locked specific cells. The feature is active only when the sheet is protected. Optionally, the sheet can be protected with a password.

EasyXLS is a spreadsheet component that facilitates the creation of Excel files and it supports to create protected Excel sheets.

EasyXLS offers a wide variety of code samples that explains how this feature can be integrated in C#, VB.NET, C++.NET, J#, PHP, ASP classic, VBS, VB6, C++, Java or ColdFusion and tutorials can be accessed staring from the following link:

How to protect Excel sheet from C#, VB.NET, Java, PHP, C++ and other?

EasyXLS component supports all MS Excel file formats including xlsx, xls, xlsm and xlsb file formats released by Microsoft over the last years like MS Excel 97, MS Excel 2003, MS Excel 2007, MS Excel 2010 and MS Excel 2013.

Furthermore, EasyXLS component supports password protected Excel files that bring the security at a higher level. The password protected Excel files are also encrypted. Check the following link for code samples:

How to protect Excel file with password in C#, VB.NET, Java, PHP, C++ and other?

EasyXLS is an Excel library that lets you create pivot charts inside Excel files programmatically.

The library can be integrated in various programming languages like .NET based (C#, VB.NET, C++.NET and J#), languages that support COM technology (PHP, ASP classic, VBS, VB6, C++), Java or languages where Java can be incorporated (ColdFusion).

EasyXLS provides code samples and tutorials for each of the mentioned programming languages. You may check the following link for directions on how to create a pivot chart in Excel in C#, VB.NET, Java, C++, PHP and other languages.

The pivot chart is in a closed relation with a pivot table. For code samples and tutorials about pivot tables visit how to create a pivot table in Excel in C#, VB.NET, Java, C++, PHP and other languages.

The library supports a wide variety of chart types that can be set for the pivot chart like column chart, bar chart, line chart, pie chart, scatter chart, area chart, doughnut chart, radar chart, surface chart, bubble chart, stock chart, cylinder chart, cone chart and pyramid chart.

All the chart elements can be formatted including chart area, plot area, X and Y axis, legend, gridlines, data table, chart title and axis titles, 3D rotation, elevation and perspective.

If not familiar with pivot charts in MS Excel or for technical related details, learn about Excel pivot tables and pivot charts.

‪Create or read password protected Excel files in C#, VB.NET, Java, C++, PHP and other!

EasyXLS™ library enables you to protect your Excel file from unauthorized access by setting passwords for opening or / and modifying the document. If you set the password for opening the file, the Excel file will be encrypted.
http://www.easyxls.com/manual/basics/password-protected-excel-file.html

‪Create Excel pivot tables in C#.NET, VB.NET, Java, C++, PHP and other, using EasyXLS Excel library! The pivot tables are reports in Excel that summarize worksheet data for a customized and clearer view over it. EasyXLS library allows you to create a pivot table in Excel, to set the data source and to arrange its data and fields into desired areas.
http://www.easyxls.com/manual/basics/excel-pivot-table.html

If not familiar with pivot tables in MS Excel or for technical related details, learn about Excel pivot tables.